It is known to have powered water sports boards including powered surf boards. However, generally the approach to date is not suitable for users that wish to maintain the surfing capability of the board.
Serious and keen surfers and other users of water surf boards may wish to use a surf board in a hydrodynamic way to maximise the use of waves to provide a ride. The development of surfboards therefore has been to focus on design parameters of the board including the material and weight of the board, the length of the board, the shape of the board as well as developments on the shape, position and number of fins mounted on the board. For example, different length and weight boards change the stability and turnability of the board. Changing the shape can also provide a different wave cutting action. However, lately the focus of developments has been on fin designs which have lead to the greatest change or control of the hydrodynamic effect of the board.
For a more recreational user one of the approaches in board design is to provide a water sports board which is merely made suitable to be buoyant with the user on a water body. Such water sports boards may have a large motor attached thereto. The motor therefore provides a major component of the board and consequently could overshadow the board's hydrodynamic functions. This could result in a powered water sports board that has a reduced hydrodynamic capability.
However a concern for the serious surfer can be the amount of energy required to move to a position at which the serious surfer can catch a wave. One factor impacting on the amount of energy consumed is typically the distance which the surfer has to travel from the end of one surf manoeuvre to the start of the next. Another factor is the number of waves which the surfer has to cross in order to get to the wave catching position. One way of reducing the amount of energy consumed is to have a jet-ski rider or even small boat user drag the surfer back through the surf out to the wave catching position. However this requires someone extra to be available for use by the serious surfer. This option can be generally available during competitions. However at recreational surf beaches for safety reasons such vehicles are banned from operating in surfing or swimming areas.
Another option to reduce the energy exerted by a surfer paddling to the wave catching position is to motorise the surf board. However, it will be generally of importance to the serious or keen surfer to not negatively affect the surfability of the board through the mechanisation thereof.
An example of motorised board can be found in US patent application number 2003/167991 which provides a kit for converting a conventional surf board into a motorised surf board. The kit includes an electric motor which is built directly into a rubber or fin. The fin is attachable to the surfboard so that no structural modifications to the board are required in order to incorporate the electric motor into the board. Another example of such a fitment is German patent number 3139816.
These designs suffer from a number of deficiencies including the increased likelihood of a surfer accidentally coming into contact with the rotating propeller. This will be most undesirable. Furthermore, the design could result in a weakening of the fin in order to allow the electric motor to be fitted thereto. The electric motor most likely will also have a short operating period due to the lack of battery storage capacity. An increase of the battery storage capacity could impact negatively on the hydrodynamics of the fin especially when considering how the electrical motor is secured to the fin in the US and German patent matters.